As a glass sheet structure providing a higher heat-insulating performance than a single glass sheet, there is known a double glazing comprising a pair of glass sheets assembled together with an air layer interposed therebetween as a heat-insulating layer. This type of double glazing, however, has the problem that the significant thickness of the glazing tends to impair the aesthetic appearance including that of the sash. Then, as a double glazing having smaller thickness yet providing superior heat-insulating performance, there has been proposed a double glazing in which a plurality of spacers (cylindrical spacers formed small so as not to impair the aesthetic appearance) are distributed between the pair of glass sheets and a sealing member made of e.g. low melting-point glass is provided between and along the entire peripheral edges of the glass sheets so as to keep the space under an evacuated condition.
By providing the respective spacers and the sealing member, a predetermined distance between the two glass sheets may be maintained although the space is evacuated. With this type of conventional double glazing, however, the spacer is formed of material (e.g. stainless steel, nickel, molybdenum, tungsten, tantalum, titanium, ceramics) having a high strength and low tendency of plastic deformation so as to be able to maintain the predetermined distance between the glass sheets against not only a normal static external pressure normally applied in the direction of sheet thickness but also against an impact dynamically applied in the sheet thickness direction.
With the conventional double glazing described above, it is possible indeed to constantly maintain the distance between the glass sheets at a predetermined value due to the high strength and low elastic deformability of the spacer per se. However, since the spacer per se has a high strength and low tendency of plastic deformation, when the double glazing is subjected to an impact, it is difficult to relieve the impact applied in a concentrated manner at the point of contact between the spacer and the glass sheet, so that the glass sheet tends to be broken.
Accordingly, the object of the present invention is to provide a double glazing which can overcome the above-described problem and which cannot be readily broken by a dynamically applied external force.